Here's a Ted Talk from 2002, George Dyson on the secret Project Orion, which was a plan to send a spacecraft to Jupiter and Saturn propelled by nuclear bombs. Dyson's father, Freeman Dyson, worked on the project.

We talked briefly about Orion an a recent FastForward Radio; I mentioned that I had heard of a similar idea proposed for interstellar travel, but had never heard of this variation on the idea. But what Dyson is describing here is obviously no variation -- this was the original pan.

Ultimately it was killed by NASA. One of the things that strikes me about this project is the sheer, brazen scope of it. There was a time when the US government would entertain such magnificent visions. It's hard to imagine them doing something like this today. The Space Elevator is an idea of about the same audaciousness, I suppose. Will NASA step up?

We'll see.

The other part that caught my attention was that the plan (apparently) was to launch the Orion rocket from Earth! That just seems crazy. Dyson notes that when NASA finally took a look at the project -- before rejecting it; it was originally a highly classified Air Force project -- their plan was to launch components of Orion into orbit via Saturn V's and then assemble them into the larger spacecraft that would fly to Mars. That would seem to make a lot more sense, if only because we would thus avoid having to detonate all those nukes within our atmosphere.

One very interesting tidbit -- Dyson says there is a secret cabal within NASA still looking at Orion. Of course, the fact that they had to go to him to get a good deal of their background information on the project doesn't instill me with a lot of confidence that they will be doing anything with the idea any time soon.

Still, it's an intriguing possibility. Maybe the way forward with Orion would be to build the Space Elevator first, use it to launch all the component materials into orbit and then take it from there. That way, even if it didn't work ot, we'd stil have the Space Elevator.

Although I have this feeling that - by the time we get the Space Elevator going -- we might have a workable fusion propulsion system, which would make Orion obsolete.